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Objective To evaluate the effect of regional hypothermia on limb ischemia-reperfusion (I/R) injury in a rabbit model of hemorrhagic shock.Methods Eighteen healthy adult New Zealand white rabbits of both sexes,weighing 2.0-2.5 kg,were divided into 3 groups (n=6 each) using a random number table:sham operation group (S group),limb I/R group (I/R group) and regional hypothermia group (RH group).Rabbits were shot with 0.25 g steel ball with a 7.62 mm smoothbore at the middle and lower 1/3 of the left hindlimb in I/R and RH groups.When the blood pressure was stable for 30 min after injury,blood was drawn via the right femoral artery at a rate of 2 ml/min until mean arterial pressure decreased to 45-50 mmHg.Then a rubber tourniquet was used to ligate left hindlimbs 10 min later.The injured limb was cooled down for 4 h after applying tourniquet to maintain the subcutaneous temperature at 9-11 ℃ in group RH.After tourniquet was applied for 4 h,perfusion was restored and lasted 6 h.After catheterization (T0) and at 2,4 and 6 h of reperfusion (T1-3),blood samples were collected from the right femoral artery for blood gas analysis and for determination of tumor necrosis factor-α (TNF-α),interleukin-2 (IL-2) and IL-6 concentrations in serum (by enzyme-linked immunosorbent assay).The animals were sacrificed at T3,and tissues around the margin of the inferior lobe of right lung were obtained for examination of the pathological changes which were scored and for determination of wet to dry weight ratio (W/D ratio).Results Compared with group S,the respiratory rate was significantly increased and PaCO2 was decreased at T2,3,the pathological score and W/D ratio were increased,and the concentrations of TNF-α,IL-2 and IL-6 in serum were increased at T1-3 in I/R and RH groups (P＜0.05).Compared with group I/R,the respiratory rate was significantly decreased and PaCO2 was increased at T2,3,the pathological score and W/D ratio were decreased,and the concentrations of TNF-α,IL-2 and IL-6 in serum were decreased at T1-3 (P＜0.05),and the pathological score was significantly attenuated in group RH.Conclusion Regional hypothermia can reduce limb I/R injury in a rabbit model of hemorrhagic shock,and the mechanism may be related to inhibiting systemic inflammatory responses.
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Objective To evaluate the regional cerebral metabolic changes in different episodes by magnetic resonance spectroscopy (MRS) after explosive brain injury in rabbits. Methods Fortyfive New Zealand white rabbits were randomly divided into eight groups, ie, normal control group( 10 rabbits) and trauma group (35 rabbits). The explosive injury in trauma group was induced by explosion of 600 mg TNT equivalent of paper detonators at 6.5 cm above the rabbit brain. The rabbits in trauma group was divided into 1,6, 12, 24 hours, 3, 7, 14 days subgroups (6 rabbits per group). The survival rate was observed at different time points after explosive injury. The MRS was used to detect the regional cerebral metabolic changes including N-acetylaspartate (NAA)/creatine (Cr) ratio and choline(Cho)/Cr ratio as well as evolution of blast injuries over time. Results The rabbits survived for overseven days in the trauma groups, with typical brain contusion manifested by pathological and conventional MRI. Compared with the normal control group, the NAA/Cr ratio was markedly decreased at one hour after injury, slightly rose again at 24 hours and fell again after seven days. The Cho/Cr ratio was markedly increased at one hour after injury, slightly fell again at 12 hours and rose again at three days after injury.Conclusions MRS can manifest the regional cerebral metabolic changes of rabbits with explosive injury at different time points and hence provide a theoretical basis for understanding the local tissue changes and determining the type of tissue damage after blast injury.
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Objective To study the characteristics of the sciatic nerve injuries inflicted by highvelocity triangle fragments in swine.Methods According to the injury position,14 swines weighing (34.29±5.2)kg were divided into two groups.All swines were shot by 0.37 g triangle fragments at (773.1±12.4)m/s aimed at the midpoint of the lateral body surface projection of the right sciatic nerve in Group A(n=7)and at 2 cm aside from sciatic nerve in Group B(n=7).The entrance,exit and length of wound tract,distance between nerve and wound tract were detected,and the pathology of sciatic nerve and wound tract at 48 hours after injury were observed under light microscope and electron microscope.Results The course of the fragments was deviated to different extent.Six sciatic nerves were in primary wound tract,four of which were lacerated and ruptured at different degrees.The light microscope showed pathological changes including severe hemorrhage and edema,leukocytic infiltration,neurotmesis,axonotmesis and light myelin coloration;while electron microscope showed severe degeneration of myelin sheath and neuraxon distortion.Six nerves(one in Group A and five in Group B)were in the concussion zone,with the distance between sciatic nerve and primary wound tract for(2.07±0.45)cm.Hyporrhea and hyperemia under perilemma and perineurium,partial nerve fiber disrupt and axonotmesis were observed by light microscope and partly myelin sheath delamination by electron microscope.Two nerves (one in Group A and another in Group B)were in the contusion zone,with moderate pathological changes.Conclusions The track of high velocity triangle fragments is unstable in the tissues.High disrupt rate,severe and wide extent lesion,early Wallerian degeneration are the main characteristics of direct injuries of swine's sciatic nerves.Indirect injuries can induce pathologic changes too,for which the lesion severity is related to the distance between nerves and primary wound tract.
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Objective To explore the characteristics of the changes of several metabolic and biochemical indices in dogs with both hindlimbs injured by kinetic weapon. Methods 12 animals were divided into 4 groups (Group Ⅰ, injured by regular weapon; Group Ⅱ,Ⅲ,Ⅳ injured by imitative kinetic weapons with different energy respectively). Levels of plasma Na+,Ca2+,K+ glucose, AMY, LDH, CK and serum T3,insulin,TSH were determined before and after injured. Results ①Local wounding conditions and distant organs' injuries in group Ⅱ,Ⅲ, and Ⅳ were more serious than those in group Ⅰ. ②Levels of plasma glucose in group Ⅱ,Ⅲ and Ⅳ were inereased significantly after injury than before(P<0.05), but not in group Ⅰ. Levels of Na+,Ca2+,K+,AMY,LDH in 4 groups had similar changes after injury while levels of CK in group Ⅱ,Ⅲ and Ⅳ were inereased significantly than that in group Ⅰ (P<0.05). ③After injury, levels of T3 in serum of all animals showed a decreased tendency and that of insulin decreased more significantly (P<0.05). There was no difference between every two groups. Levels of TSH in group Ⅱ,Ⅲ and Ⅳ were increased significantly after injured than before (P<0.05), but not in group Ⅰ. Conclusion Not only local severe injury but also more serious injury in distant organs and more obvious changes of metabolic and biochemical indices can be induced by kinetic weapons than regular weapons.
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Objective To provide experimental basis for the weapon design by means of observing the injury by super high velocity fragments. Methods Nine male Huanan dogs were wounded by super high velocity aluminium bullet shot from an explosive gun with the energy of 15 360,12 643 and 8 144 J respectively, the degree of injury of local tissues and the pathological changes of main organs were observed. Results The injury degree of local tissue wounded by the super high velocity fragment of 15 360 J was similar to that of 8 144 J, and was more severe than that of wound by 12 643 J. Conclusion The injury degree is closely related to the mass and the momentum of the super high velocity fragment, the more the momentum is,the greater the execution is. No significant relationship exist between the injury degree and the energy.
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Objective To observe the characteristics and rules of craniocerebral injury resulting from a high explosive shell to provide the bases for treating explosive injury. Methods A total of 36 sheep were distributed at the distance 6 to 48 m away from the explosive center and the shell was exploded electrically at 7 m above the earth. At the same time, the velocity of fragments and shock wave pressure were determined. Gross and pathological observations were performed after injury. Results Among all sheep with fragment injury, craniocerebral injury was 32%. Their immediate death rate was 75% and all died 6 h later. The incidence rates of penetrating wound and blind wound were 75% and 25% respectively. Pollution of wound track was heavy. The percentage of head lost was 50% in sheep and 50% of injured animal suffered from comminuted fracture of skull base. Bleeding was found extensively on the surface of the cerebrum, even medulla oblongata was involved. Hemorrhage, edema, rupture of small blood vessels and degeneration of neuron were found at the regions 4 cm away from the wound tract with light microscopy. Combined blast injury was found and occurred most often in the abdomen and limbs, both accounting for 62.5%, and combined thoracic injury was the third, up to 50%. All the animals of craniocerebral injury combined with lung blast injury. Conclusion High explosive shells destroy cranium badly and extensively. Many skulls are lost and the cranial base is readily fractured. The wound track is heavily polluted. Combined injury is more often occurred.
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Objective To investigate the surgical management of a gun shot wound of blood vessels and immersied, and evaluate its primary effect. Methods 100 rabbits were divided randomly into simple wounded group(SWG,n=50) and seawater immersion group(SIG,n=50).F emoral arteries were impacted by 0.38 gram steel spheres with velocity of 600 ～800 meters per second fired by 7.62 mm rifle. Animals in SIG were immersed in artificial seawater (pH 8.2～8.4, salinity 25.4,temperature 21℃) for 60 min, o f which those in SWG were spared. Grossly injuried artery was excised and restor ation of blood flow was reconstructed by end-to-end anastomosis or reversed au togenous venous grafting or cryopreserved arterial allografting. At 24 h,7,1 4,21 days after operation, blood flow was examined by Doppler ultrasonic detecti on and part of anastomotic sites and graft were collected for pathological obser vation. Results In completely transected injury, the patency in SIG was 80.00%,while that in SWG was 86.67% in the first 3 weeks. In arterial c ontused injury ,patency in SIG was 86.67%,and that in SWG was 82.35% at the same time. Thrombosis occurred mostly in the first postoperative week. Atypical endo thelial cells were found at the anastomosis sites in the first postoperative week, and the anastomosis sites were lined with endothelium in 3 weeks postopera tively. Conclusion Early curative effect could be obtained. Whe n grossly injuried artery is excised and followed by a routine surgical procedur e in the treating gunshot wounds immersed in seawater.
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AIM: The influence of the seawater on the lipid peroxidation of the muscle tissue wounded by firearm was studied. METHODS: Both two limbs of rabbits were wounded by the steel ball of 250 mg. The wounded rabbits were divided into two group: One is seawater immersed group (SIG), which was dipped in artificial seawater for 30 min. Another is the single wounded group (SWG), which wasn't dipped in seawater. Then, muscle tissues 0.5 cm (A area), 1.5 cm (B area) and 2.5 cm (C area) from wound edge were cut for biochemical analysis at 3, 6, 12, 24 h of post-wound, respectively. The contents of ATP, MDA and SOD activity of all these tissues were detected, pre-wounded muscle tissues were used as control group. RESULTS: The content of MDA in SIG increased obviously at 3, 6 h, respectively, but it decreased slightly at 12 h and increased again at 24 h. The change in MDA in SWG is similar to that in SIG but more slightly. The changes in both the activity of SOD and the content of ATP in two groups is similar to that of MDA. CONCLUSION: Seawater induced more serious lipid peroxidation in the muscle tissue wounded by firearm.
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AIM: The influence of the seawater on the lipid peroxidation of the muscle tissue wounded by firearm was studied. METHODS: Both two limbs of rabbits were wounded by the steel ball of 250 mg. The wounded rabbits were divided into two group: One is seawater immersed group (SIG), which was dipped in artificial seawater for 30 min. Another is the single wounded group (SWG), which wasn't dipped in seawater. Then, muscle tissues 0.5 cm (A area), 1.5 cm (B area) and 2.5 cm (C area) from wound edge were cut for biochemical analysis at 3, 6, 12, 24 h of post-wound, respectively. The contents of ATP, MDA and SOD activity of all these tissues were detected, pre-wounded muscle tissues were used as control group. RESULTS: The content of MDA in SIG increased obviously at 3, 6 h, respectively, but it decreased slightly at 12 h and increased again at 24 h. The change in MDA in SWG is similar to that in SIG but more slightly. The changes in both the activity of SOD and the content of ATP in two groups is similar to that of MDA. CONCLUSION: Seawater induced more serious lipid peroxidation in the muscle tissue wounded by firearm. [